Does anyone know the science behind using butter as a greaser?i need to know for research but CAN NOT find a single website to tell me WHY it works

It has to do with fat polymerization. I believe that the chemical structure of butter (a saturated fat) is the reason it's the better grease. When heated, fat forms a polymer, much like Teflon, making the surface of the pan non stick. Fats (like butter, oil, etc) are long-chained molecules (we're talking very long) that when heated will cross-link and form a polymer (polymerization). The more cross-linking the strong the polymer. Mono-unsaturated or poly-unsaturated oils don't have the extensive chain that butter and lard have which is probably why they aren't better greasers. I've probably butchered the explanation a bit but you get the general idea. Go research "fat polymerization".

As to "why grease a pan at all": proteins love to stick to other molecules like metals, especially when heated. Here's a short blurb from a book on Food Cooking:
https://books.google.com/books?id=I5FVn9EjHH0C&pg=PA218&lpg=PA218&dq=why+do+proteins+stick+to+metal&source=bl&ots=J1buuEoaFB&sig=fxa8p__xMbkJslYw2uDqcoSkEYc&hl=en&sa=X&ved=0ahUKEwijguWpt9DYAhUB8GMKHaMPBMIQ6AEIYjAI#v=onepage&q=why%20do%20proteins%20stick%20to%20metal&f=false

Here's a link about proteins in general: https://www.ncbi.nlm.nih.gov/books/NBK26911/

Since protein is quite reactive with metal surfaces above 175F, the fat polymer interferes with this reaction and the protein (eg. food) cannot stick to the pan.

I've really simplified the explanation. I only have a Bachelors Degree in Chemistry and it's been awhile since I've worked in R&D, but this is my understanding of fatty molecule chains and protein.

So look into fatty molecule structures ("chains"), fat polymerization and possibly, protein adsorption.

It is complicated, check out Harold McGee on Food and Cooking, especially chapter 14, Cooking Methods and Utensil Materials, where there is a section on frying: "the oil has several roles to play: it brings the uneven surface of the food into uniform contact with the heat source, it lubricates and prevents sticking, and it supplies some flavor." Also Chapter 13, The Four Basic Food Molecules, the section section Fats and Oils, and subsection on fats and heat. There are also sections on the chemical structure of fats and oils, Maillard reaction, etc. The latter probably comes into play at the point of contact between the cooking vessel and the food. He doesn't give a simple, single answer but this is a start.

I don't know the science but butter tastes awesome, that's why you need it! Seriously though , humans have a fat tooth as well as a sweet tooth, probably as a survival tool as fat carries a lot of calories which would be critical during early human evolution. Fats also help food not stick to the pan ( think how oil lubricates your car engine ) . Try Alton Brown, he looks at the science behind cooking http://www.foodnetwork.com/shows/good-eats/episodes/there-will-be-oil

Check Serious Eats, The Food Lab and Alton Browns Good Eats. They explain the science behind a lot of cooking techniques.

Ask yourself which science is involved?
(Likely chemistry; possibly physics having to do with the material composition of the pan.)
Talk to one or more people in those subjects (scientists, research librarians); who can direct your research to useful areas.